Steering disconnect for aircraft



E. H. HARTEL STEERING nrsconnzc'r FOR AIRCRAFT July 5, 1960 2 Sheets-Sheet 1 Filed July 29 1957 INVENTOR. ERWIN H. HARTEL FIG. 3

ATTORNEY y 1950 E. H. HARTEL 2,943,867

STEERING DISCONNEC'I' FOR AIRCRAFT Filed July 29, 1957 2 Sheets-Sheet 2 INVENTOR.

ERWIN H. HARTEL TTTTTT EY v 2,943,867 STEERING DISCONNECT FOR AIRCRAFT ErwinH. Hal-tel, Cleveland, Pneumatic Industries porafion of Ohio Filed July "29, 1957, Ser. No. 674,858 1 Claim. (Cl. 280-442) Ohio, assignor to The Cleve- Inc., Cleveland, Ohio, a cor- V This invention relates generally to landing gears and more particularly to a lock mechanism to which a towbar can be attached when the aircraft is to be towed on the ground wherein the connection of the tow-bar automatically disconnects the steering linkage so that the wheel is free to be swiveled through a full 360 by the tow-bar.

Un d. Stairs When an aircraft is moved on the ground in confined 7 places it is customary to use a towing tractor or the like'which is connectedto the nose landing gear of the aircraftby a tow-bar arranged to turn the nose wheel and pull the aircraft so that the aircraft will follow the tractor. v In the past the steering linkage has been manudisconnected when the tow-bar is connected to the aircraft "so that 'the nose wheel can be freely '{s'wiveled theitow-bar, Thishas not only requiredfthat the gr und handlingpersonnel perform a separate operation em in addition has resulted'in damage if'the ground g per s'onnel neglect to disconnect the steering linkfor'e towing or re connect' it after towing. a n s, an important object of this invention to provide f ce understood that if for some reason the landing gears other than the nose gear are to be swiveled in any particular application, the mechanism according to this invention could be applied equally well to any such landing gears. V g

Referring .to the drawings, Figurel illustrates the normal method oftowing an aircraft wherein a ground handling tractor 1'0 isconnected to. an aircraft 11 by a tow-bar 12. The aircraft 11 is provided with a noselanding gear 13 on which is mounted a landing wheel 14. The tow-bar 12 is connected to the nose landing gear 13 and used to move the aircraft on the ground nd also turn the landing wheel 14 so that the aircraft 11 will track or follow the tractor 10. A typical landing gear 13 includes an upper telescoping member 16 adapted to be mounted on the frame of theaircraft and a lower telescoping member 17 which is axially movable relative to the upper telescoping member '16. In normal practice fluid spring and shock absorber means are incorporated into the 'telescoping'members 16 and '17 to resiliently urge the lower telescoping member 17 toward the extended position so that the weight ofthe aircraft can be resiliently supported on the landing gear. v

A wheel support member 18 on which the wheel is journaled is in turn mounted on 'the lower end of the lower telescoping member 17. In the embodiment shown turning of wheel 14, for steering is accomplished by a power steering inechanis'm including a fluid motor 319, connected betweendhe upper. telescoping member 16 and 'a steeringcollar :21 which is journaled on the lower end portion of the member 16' The steering collar'iZl .is in turn connected to the lower collar 22 by convena j lariding gear 'with'means which automatically 'permit 1.

r; wivelingjof the landing wheel when thetow-bar is fc'onnected for ground handling. It another'impo'rtant object of this invention to provide lock means for an aircraft landing gear which auto- 22.1011 the lower telescoping member maticallyreleases to permit free swiveling of the landl 'urther gbj e'cts and advantages will -appear from the follov ving descriptioniand drawings, wherein: V I "fFigure l is'a pictorial view' illustrating how an aircraft 'istowed on the ground with a ground handling tractor; 7 V V 1 V ligure 2 is an enlarged side elevation of a nose landing 'gear incorporating this invention with a tow-bar connected'thereto;

Figure, 3.is an enlarged side elevation in'longitudinal section or thepreferred lock mechanism; a

Figure 4 is a bottom View of the lock mechanism shown inthe'normal locked orfiight position, and; v ",Figure 5 is arviewfisimilarnto Figure 4 showing the position the elementsassumednwhen a tow-bar is connected and the lock mechanism is in the unlocked position.

In normal practice the nose landing gear is the only one that is steerable so the discussion that follows refers only to the nose landing gear, but it should be tional torque arms 23; The torquearms '2'3rpreventrelarive-rotation between the two collars 21 and22while ng axial motion therebetweenr Therefore, it :is a to axially i fixthe'ste'ering collar '21 on the up er telescop ng membe 116' andaxially 17.. -The lower collar 22' is 'jo'urnaled on the lower telescoping member 17; and rearranged so that it can; either be rotationally lbckedo'l l the member '17 for normal operation or the aircraft, or made free to rotate relative thereto for ground n l n a1 r q normal power steering of the aircraft when the 'air- .craft is operating-under its ownpowe'r, the fluid motor '19 jis used to turn the "steering collar 21 relative tothe upper telescoping member 16 and in turn rotate the lower steering collar-.22 through the torque arm connection. A look mechanism 24 normally prevents relative rotation between the lower member 17,'the wheel support '18 and the lower collar 22, so rotation of the latter produces rotation of the formerland in turn steers the landing wheell l. The lock mechanism is operable to an unlocked position at which time the wheel stipport aud landing wheel 14 are free to rotate relative to freely swiveled'. l V p Reference should now befrnade to Figures 3 through S fQr detailed description of the lock mechanism 24. The wheelsupport 18 is provided with a mounting sleeve 26 formed with a central bore 27 into which the meaend of the lower telescoping member 17 projects, A bearing 28 may be positioned between the mounting sleeve "the lower collar 22 so that the landing wheel 14 canbe Z6 and the lower telescoping member 17 to'prevent lateral movement therebetween. In order to prevent relative rotation between the mounting sleeve '26 and the lower telescopingamember 17, I provide a hollow pin 29 which extends laterally through the mounting sleeve 26 and the lower telescoping member 17. Those skilled in the art will recognize that this structure in effect makes the lower telescoping member 17, the mounting sleeve 26 and the wheel support 18 a unitary member so that the lower l atented July. 5., 196( the lower collar i 7 position, 1.

the wheel is turned for steering'purposes. j a

The lower collar 2 2 is jpurnaled on bearings 31 and 32 and isformed with an inwardlventending flange .por- 'tion'35 which projects} between radially extendingjljeaf- "ing" portions 3 3 jand 34. The beaiin'g'ZSjis' for'med with "a. flange 36 which prevents {upward movement, of; the

t atably carried by, the lower telescoping member 1 7. j Inorder to provide "the"lbckingfbetweenjthe lower ';collar 22 .and the,- mounting sleeve 26 I p'rovided a lock bar 37 secured to a' slidingstelm 38 by anutfastener 73 9. The pin 29 is. formed withafirstfaxiallbore 41am as econdlarger co-axiallbore 42 'joined by a' shoulder 1 43? stem 38 is formed witha firstfpdrtion 44,.hav- 'jing a diameter adapted tojclosely fit the bore '41 "secondportion' .46 whichfelosel'y fits'the here 42. i The first and 'seco'ndporltions 44 and. 46 are joined by a- {shoulder 47 and a spring 48 extends between the two "shoulders 43and; 47 resiliently biasing t e stem 38 and "lockhar 37 toward the locked position: shown in Fig- Cure 3. The mounting sleeve'26 is formed with a'pair e of; spaced lugs .49 which. providejopposed' guide surfaces 5 1 and 52*between which the lower end of the .lock han 37 .is positioned. The lock bar' ,37 isjtherefore, restrained against'rotation about the ioentral'axis er the stem 3 8 bi1t is movable along thei iaxis' Of the 'stem'38 against theaction oi the spring 48.-Thelower 'jsleeve 22'is formed with'a peripheral cylindrical surlface3 and amQiQh-54 (best shew inl Figurei 5) :which fis a da'pted to receive the lock b'a'r' 37"when*the"n1ounting sleeve; 26 and, the lowenco ar,,22'; 'are properly '7 ro'riented".,fv (11 33%: f 53 ff? i In the locked;pos ition, the lock Ibal" 37 fi's positioned e T t e rp 't 154i o relat v r fi tweea' the flower 'colIarFQZiandQthe'mounting sleeve' Iis' prev f wfl yeri he I stemfifii nd ithelo kr bar provided with a f orke d'end halving laterallyl spaeed tears '59iadapted to fit over the tow lugs-56 and be piv lffotally connected thereto by the tow bolt58. :The stem,

38*is proportioned so flthat' the portion; 46 normally fproj'ectsbetween the lugs 56 when the lock bar 3.7 j s fin' the" locked positiongf ln order -to 'pll s'e'r tlth bolt 58itl1'r0ugh th ei lugs 56, it islnecess arylo m th "stem. '38 inwardly a predetermined extent calculated; to

par

mov''the lock barf37 outlof'thelnotch- Q4,}o unlocked position. To facilitatethe me'v'eine audit;

7 e (1.2. 1 p e V V 3.7 are oved;-x- 1 56 i h so'th i h up e n a li o k' i j 7 elearsl thel'notch 54, thernounting sleeve 2611's freef'to f ,rqta e' l l fiv jito the: t qwcrgmllar 1.22. j In order tog r- -ividej' movement gf the. stem 33110 the j unlocked position 2151' :it isflmerely; necessary to overcome ftheiifor'clelof itlie i The mounting 1 "telescoping member 17 will'rotate with the wheel'14 when n fore the mounting sleeve 26 is free to rotate-relative to the lower collar 22 when the "toW BaniFconfieEtedTto 'enable towing of the aircraft without dangerfof injury" to the landing gear on its steering mechanism. As soon as the tow-bar 12 is disconnected by removing the towbar 'bolt 58 the action pt the spring 48 urges the stern h bearing "31 and downward movement of the bearing: 32 .is preventedby .theupper end of the mountingsle'ev'e :in the forward direction will the duringi' groundlhandlingjand there s pilot ,Q i PIeting' a take-oil with-'a' 'steering system.

tions' of the structural deta l m P '28 lock bar 37 toward the-lock position. If the mount-' into the neutral or forward position wherein it; is v gn i ,with central axis of the aircraft, thereupon enabling e lock bar 37 to snap into the notch 54.

The above disclosed structure provides; s inip1e1 y cost, essentially "fool-proof methodof providingire; swiveling for a landing gear during ground-handling of an aircraft. Because thestemfiti and the'lock'b 37. .move only horizontally; the impact of landingfand 7 like will not tend to shake the bolt'toan unleckedfpq V 'sition. With this mechanism it impossible to e, :c

the landing gear byf or'getting to .diseorinect the stee connected; w Although v are illustrated, it will artin'g friom'lthe niodeiot f iope he ariedi widely'withoutf mod y gr V sleeve 26' isfOrmed afpair of;

parallel towjugs 456 with queen either side .eflthe 15er- V N 1 Qf h6 stem' -lis ll 'l'he fotw' iigs 56Tarfe formed 1 witfijco-axial' 'boresl57 adaptedito receive a j'tow-bar' e BoltQSS (shown in 'Figure'5)fwhich,is usecl tofconnect thetow-bar'lz to the. nose 'gear' 13. "Ihetow-ba'r lz i stem 38 to theunlocked position jtheieudofitheiptirtion 7 4e as 'formed with opposed"cammingisurfaces fl:so that i V jlgqliniertionpi theito w bar bolt s sgthrough thef lugs 56 automatically f mdvee the lock ist'eni 3 8i tq me unlocked Those skilled in thei'art willtriecognize.

e e v at by using r the above described structure the lockimechanism 24 wis;"atitorna t ically sunloekedjorswiveling motion-anytime Ethegtow-bar connected toithe gear-f Th V lockedjpositionl in Qwhichl it; diseng'ag'es s I 7 permitsielative rotation between said. collarand se I 1, V lock element projectlng'be een said ibolies. onsai d Accordingly, the append aforesaid detailed description are scoperof V invention. -"Ic1aim; r

r1 pl tobe mounted on an'aircraft', Ia p 1ston rn ber teles p- 'ing into said cylinder.member? axiallfi'mev lefr thereto; a landing wheeljourn'alled' on 'saiqpisteu m her, a steerable collara tially fixed ana etatapiefie tive .to said piston member, la l ock as'semblyincludi'n 'a lock element mounted onfs a'id pisgdnmem e for H izontal movement relative. theretojflom la le ea tioninwhich .it' engages; said eqna aaa re a re tionfthereof relative to saidlp te niepapr A landing gear'compi'i sing a e hnder me e 19 1' m mb were 559 ii .P} "alignedbors 'it' p ,v V ceive a'boltconnectingisa I tow b'ar 'whenf'it is in said mekd position 'a 'nd being niaint in the junlocked position when .s'aid; bolt connee tow bar 'andpiston memb r, and aspring resiliently ing said lock' element towards'said locked' pbsiti f!inieaqegjeie ngfiieamis sien 1 NlTE STATES PAIE IS 7 wood: 652 1945; 2,544,278 'Nickell *:Ma -6,:; 19,51 K 25 1551; cup e M 15,1956: f; f: r i :1: 1 V l 

